The goal of this research is to understand how the cerebellum aids eye movements. We know that the cerebellum is important in every movement we make, but we do not know exactly what it does or how it does it. We can make progress faster by investigating the cerebellum with eye movements than with limb or other movements because we know much more about how the brain produces eye movements than any other movements. Our results will also help us understand how the brain produces eye movements. Eye movements are an important part of our lives. Every day we make tens of thousands of eye movements to look at things of interest and see them clearly. Abnormalities in eye movements severely reduce our ability to read, see, and visually guide our other movements. Among other projects, we are investigating the role of the cerebellum in the ability to make eye movements accurate after something has made them inaccurate. The cerebellum has been implicated in the unconscious learning that keeps our movements accurate, but we do not know what role it plays. In 1997 we published a detailed description of how normal monkeys adapt their rapid eye movements. This description will help us investigate how the brain modifies movements to keep them accurate. We also published a description of the role of the caudal fastigial nucleus in the slow smooth-pursuit eye movements that we use to look at slowly moving targets. Finally, we submitted a paper on how making many repeated rapid eye movements affects the performance of these movements. This information will help us correctly interpret data on eye movement adaptation that we collect from monkeys.